In typical commercial electrographic reproduction apparatus (copier/duplicators, printers, or the like), a latent image charge pattern is formed on a uniformly charged charge-retentive or photo-conductive member having dielectric characteristics (hereinafter referred to as the dielectric support member). Pigmented marking particles are attracted to the latent image charge pattern to develop such image on the dielectric support member. A receiver member, such as a sheet of paper, transparency or other medium, is then brought into contact with the dielectric support member, and an electric field applied to transfer the marking particle developed image to the receiver member from the dielectric support member. After transfer, the receiver member bearing the transferred image is transported away from the dielectric support member, and the image is fixed (fused) to the receiver member by heat and pressure to form a permanent reproduction thereon.
The latent image charge pattern is formed by exposing the dielectric support member to actinic radiation in a desired pattern corresponding image-wise to information to be reproduced. Such exposure may be accomplished optically or electronically. That is, a reflected light image of information to be reproduced may be optically focused on the uniformly charged dielectric support member to alter the charge in an image-wise pattern. Alternately, a light-emitting device, such as a laser or light-emitting diode (LED) array, may be activated according to appropriate electrical signals to alter the uniform charge on the dielectric member to form the desired image-wise charge pattern. Furthermore, in recent high speed optical copier/duplicator devices, it has been common practice to provide an electronic activated light source to form image-wise charge patterns, or to annotate optically formed charge patterns.
The known light emitting devices, commonly referred to as writers, must be accurately located relative to the respective dielectric support members to provide a focused image-wise charge pattern thereon. Furthermore, the known light emitting devices must be removable for maintenance or replacement, or for service on the reproduction apparatus itself. In well-known reproduction apparatus utilizing light-emitting device, such as a laser or (LED) arrays, it is common practice to disconnect the light-emitting device to facilitate removal prior to service and maintenance. This complicates service procedure, and makes it difficult to maintain the desired accurate placement of the light-emitting device within the reproduction apparatus.